The present invention relates to the derivatives of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide usable as an active ingredient of herbicides, and to the herbicidal compositions containing such derivatives.
Rice, wheat and corn are the important farm products, and use of herbicides is essential for protecting these crops from harm by weeds so as to attain an increased yield.
It is known that the derivatives of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide have a herbicidal activity. For instance, Japanese Patent Application Kokai (Laid-Open) No. 193406/82 discloses a herbicidal composition containing as its active ingredient a derivative of 1,2,4-triazole represented by the formula: ##STR2## wherein R.sub.1 is a hydrogen atom, a fluorine atom, a chlorine atom, an iodine atom, a lower alkyl group having 1 to 3 carbon atoms, an alkyl group substituted with fluorine, a nitro group or a methoxy group; R.sub.2 is a hydrogen atom, a chlorine atom or a methyl group; and R.sub.3 is a hydrogen atom or a methyl group.
Also, in Japanese Patent Application Kokai (Laid-Open) No. 98004/84 is disclosed a herbicidal composition containing a derivative of 1,2,4-triazole represented by the formula (I): ##STR3## wherein R.sub.1 and R.sub.2 represent independently a hydrogen atom, a halogen atom, an alkyl group or a halogenoalkyl group; R.sub.3 is a hydrogen atom, a halogen atom or an alkyl group; and R.sub.4 is a cyano, carbamoyl, thiocarbamoyl, N-alkylcarbamoyl, N-halogenoalkylcarbamoyl, N-methoxyalkylcarbamoyl, N-alkenylcarbamoyl, N-halogenoalkenylcarbamoyl, N-acylcarbamoyl, N-halogenoacylcarbamoyl or N-methylthiocarbamoylcarbamoyl group.
These derivatives, however, are still unsatisfactory in herbicidal activity and selectivity. Therefore, development of the compounds having high herbicidal activities and excellent selectivity enabling killing of weeds alone without doing any harm to the crops such as rice, wheat, corn, etc., has been strongly desired.
The present inventors have made studies for providing a compound showing a high herbicidal activity but being practically harmless to such crops as rice, wheat and corn, and found that the derivatives of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide represented by the following formula (I) have the excellent selective herbicidal activity: ##STR4## wherein R is a straight-chain alkyl group having 1 to 10 carbon atoms which is non-substituted or substituted with 1 to 19 fluorine atoms, a branched alkyl group having 3 to 10 carbon atoms which is non-substituted or substituted with 1 to 19 fluorine atoms, a cyclic alkyl group having 3 to 10 carbon atoms, an alkyl group having 1 to 3 carbon atoms which is substituted with an alicyclic structure having 3 to 7 carbon atoms, a phenyl group or an aralkyl group having 7 to 9 carbon atoms; X.sup.1 is a halogen or an alkyl group having 1 to 3 carbon atoms; X.sup.2 is a hydrogen, a halogen or an alkyl group having 1 to 3 carbon atoms; Y.sup.1 is a hydrogen or a fluorine; and Y.sup.2 is a hydrogen or a fluorine. The present invention was achieved on the basis of this finding.
The compounds of the formula (I) are different from the compounds disclosed in aforementioned Japanese Patent Application Kokai (Laid-Open) Nos. 193406/82 and 98004/84 in that the compound of the formula (I) has an X.sup.1 group and a 3-position --CH.sub.2 OR group (X.sup.1 and R having the same meanings as defined above) on the 1-position phenyl group of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide. These compounds are not found in the prior literatures.
Thus, the present invention has for its object to provide the derivatives of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide having excellent selective herbicidal activities against grass weeds and, in particular, broadleaf weeds while doing no harm to such crops as rice, wheat and corn, and the herbicidal compositions containing the derivative as active ingredient.